Austin 7 Special

Restoration/Building of an Austin 7 Special

Today I finished the little carb to blower block. I drilled the 6mm holes to bolt it to the blower and drilled and tapped blind holes to take some 5/16 BSW to 5/16 BSF studs. These are the same as the ones that attach the mechanical fuel pump to the crankcase. I have a 5/16 tap but it’s a taper tap and not a bottoming one so I had to find a bolt to chase out the thread to the bottom of the holes. I didn’t have a 5/16 whitworth bolt but I did have a 5/16 imperial which is close. I ran a whitworth die over that to make the thread correct then cut a slot in the side of it with a Dremel and flattened the end of it on the sanding disc. I could then use it as a bottoming tap to clear the thread in the casting. I then loctited the studs in.

It all fits together well. I also made sure the block matched the outlet port of the carb and I sanded the inside of the block smooth. I have to assume the port on the blower matches it since you can’t see through it when it’s bolted on of course. I used the original gasket as a pattern so it should be good.

The other thing I noticed once I bolted the carb on was that it is possible to reverse the choke lever. As it was it was set up to pull via a cable from the left. I swapped it over so now the cable will pull from the right which will suit my car better. I still need to get a rebuild kit for the carb as well as a spring and needle. I need to order those from the UK.